Magnification systems require an illumination source for illuminating the object to be magnified. In many situations, the intensity of the light illuminating the object must be kept uniform over a significant duration of time for proper imaging. In certain fields, such as microelectronic fabrication, uniform light intensity is critical to properly inspect the surfaces of microelectronic devices. Uniformity in the light intensity on an illuminated object is difficult to achieve for any significant duration. For example, the amount of light emitted by an illumination source, such as a light bulb, may change as the light bulb heats up, ages, etc. This is especially true when a high intensity light source is employed. The intensity of light provided by a high intensity light source begins to change almost immediately upon operation. Even if the intensity of the light from the light source is constant, the intensity of light provided by an illumination device using the light source would still vary. For example, as components and structures in the illumination device heat up, the geometry of the components, including the relative position of the light source and reflector, varies thus altering the intensity of light provided by the illumination device. Therefore, to maintain a constant intensity of light on an illuminated object, the power and the intensity of light produced by the illumination device must continually be tuned to compensate for the various changes.
A manual method is currently employed to tune the intensity and amount of light provided by an illumination device. The position of the light source is manually adjusted by a technician in an attempt to maintain the intensity of illumination constant over time. The size of an aperture in a diaphragm is likewise, manually adjusted, in an attempt to maintain a constant amount of light per unit of time, or power. This requires a skilled technician to make many time-consuming and error prone adjustments to the correctly position of the light source.